Yellow vat dye.



, nE'rLEv Nissan, 015 FECHENHEIM, AND Enron GERMANY, ASSIGNORS 'ro CASSELLA COLOR SAUL, 0F FRANKFORT-ON-THE-MAIN, COMPANY, A CORPORATION OF NEW Patented-Mar. 4, 1913.

.YORK. 1 V i YELLOW VAT DYE.

1,055,287 Specification of Letters Patent. No Drawing.

To all whom it may concern:

Be it known that we, DETLEV NISSEN, a subject of the Kingdom of Prussia, residing at lValdstrasse 5, Fechenheim, and Enron SAUL, a subject of the Duchy of Braunschweig, Germany, residing at Untcrmainkai 21, Frankfort-on-the-Main,

many, have invented a certain new Yellow Vat Dye, of which the following is a full descri tion.

not possess the properties of a vat color.

Although dyeing cotton slightly yellowish,

such dyeings are not fast. Moreover, when phthalic acid anhydrid is condensed with carbazole in the presence of aluminium chlorid, the reaction does not proceed uniformly.

According to this invention phthalic acid anhydrid is condensed with carbazole derivatives having a substituted imidehydrogen; not only is the reaction almost uniform but the resulting products can be transformed on heating with dehydrating agents into intenseyellow dyestuffs having all the characteristic properties of vat colors of the anthraquinone series. The dyeings offer excellent resistance to washing, light and chlorin.

Example: 30 kilos N-ethylcarbazole and 90 kilos phthalic acid anhydrid are suspended in 250 kilos nitrobenzene; 180 kilos aluminium chlorid are then gradually added, the temperature not being allowed to exceed 50 to 70 C. Hydrochloric acid is generated, and the mass assumes a greenish black color, \Vhen the reaction is complete, the mass is heated for 5 hours to 50 to 70 C. The thick but liquid mass is then placed in dilute hydrochloric acid and the nitrobenzene distilled off in a current of steam. The light brown granular residue is purified by boiling with dilute hydrochloric acid. It is Gertion.

' Application filed August 23, 1912. Serial No. 716,651.

then dissolved in hot dilute caustic soda lye, filtered off from an residue-that may be left, and the ethylcar azole-3.6-diphthaloylic acid is precipitated from the filtrate in the form of an almost colorless precipitate by the addition of hydrochloric acid. It dissolves in concentrated sulfuric acid with an intense reddish purple color, and is easily soluble in alkaline 1 es and in soda solu- 50 kilos of t e ethylcarbazolediphthaloylic acid are dissolved in 500 kilos concentrated sulfuric acid. The reddish purple'solution is heated to 100 to 105 C. until nothing soluble in alkalis remains (after about 5 hours). The melt is then diluted with ice, and the light gray precipitate which separates is washed with water until it shows a neutralreaction. It is insoluble in alcohol, ether and dilute hydrochloric acid, and dissolves in concentrated sulfuric acid with a reddish purple color. It has the following constitution:

mordanted cotton an intense pure yellow shade of eminent fastness to washing, light and chlorin.

Very analogous dyestuffs are obtained by using in place of the N-ethylcarbazole the corresponding methyl or benzyl product, and in place of phthalic acid its halogen products of substitution.

Having now particularly described and ascertained the nature of our said invention, and in what manner the same is to be performed, we declare that what we claim is:

1. The' process of producing a coloring matter, dyeing from the vat bright yellow shades fast to washing, light and chlorin by condensing an N-substituted carbazole with phthalic acid and heating the product thus obtained with concentrated sulfuric acid substantially as described.

2. The yellow coloring matter having the I dyed yellow shades fast to washing, lightconstitution and chlorin substantially as described.

I In witness whereof we have hereunto 15 l I CO NR signed our names this 9th day of August I I I l 1912, in the presence of two subscribing witl Y nesses. I

DETLEV NISSEN.

ERICH SAUL. R representmg an alkyl-group, whlch forms 10 a yellow powder or paste, dissolving in water Witnesses:

by means of sodium hydrosulfite yielding a JEAN GRUND,

brownish solution from which cotton is CARL GRUND. 

